Immigrants and their Accents

I have been told that my accent has changed. It may have, but I really have no way of knowing. I speak the way I speak and always have, atleast what I am aware of. I have never, ever deliberately tried to imitate A or B or C or whatever ... even though it is possible that over the years, I have picked up some slang/styles/whatever from the places I have lived - from people I have heard.

Some say that I sound very Indian, there is that distinctive discernible Indian accent. Some seem intrigued by some combination of Indian/English/American usage of some words/expressions. I have simply no idea what they hear that I do not hear.

So, I wonder. Why do some immigrants seem to have changed their accents while some have not changed at all? Is it a function of the language environment at home? Their schooling?

What most people do is ofcourse after the initial impression about the accents, concentrate on the content of the message as opposed to wondering about how the message is being delivered, in what strange accent.

I have noticed that some people cannot get around the accent issue - they cannot go beyond the issue of accents and lose the message or the content.